Generalize automated tests for OpenPGP keys expiration
Originally created by @intrigeri on #9402 (Redmine)
In config/chroot_local-includes/lib/live/config/2000-import-gnupg-key
we import /usr/share/doc/tails/website/*.key into the desktop user’s
keyring. Since #9112 (closed) was resolved, that now means more keys than it
used to. We already have automated tests to ensure that some of these
keys are up-to-date and won’t expire any time soon. This should be
generalized to all keys we import at boot time.
Feature Branch: kytv:test/9402-check-all-tails-openpgp-keys
Parent Task: #8543 (closed)